Train control



March 3, 1931...

c. s. BUSHNELL 1,794,582

TRAIN CONTROL Filed May 1 1924 9 Sheets-Sheet l -Ma;'ch 3, 1931. c. s.BUSHNELL 1,794,532

TRAIN CONTROL Filed May 10, 1924 951166128-31'1891; 2

(2 5 INVENTOR.

I TORNEY F IG 2 Runnjn March 3, 193 c. s. BUSHNELL TRAIN CONTROL FiledMay 10, 192.4 9 Sheets-Sheet 3 IN V E TOR.

-'TTORNEY Q' Shet's-Sheet 4 N V EN TORQ March 3, 1931. 'c. s. BUSHNELLTRAIN CONTROL Filed May 10, 1924 ll-h March 3, 1931. c, s BUSHNELL1,794,582

TRAIN CONTROL Filed May 10, 1924 9 Sheets-Sheet 5 FI G.6.1 I

FIG. 6.

I 1195 BV 188 To Eqgyb'mq Rese. om

' Z 5 @VENZOR. BY l March 3, 1931. c. s. BUSHNELL TRAIN CONTROL Fil 11924 9 Sheets-Sheet 6' km mo 7/. m. 27/ a d3 3. Eu 06 +3 MON 03 w mdm awm2 3N com 3 2m EN EN mom D 1B bmd an .ieiuavmv mEsl I IN VE TORZ March3, 1931. c, s, BUSHNELL- 1,794,582

TRAIN CONTROL Filed May 10, 1924 9 Sheets-Sheet 7 INVENTORI 6. 5.

. ATTORNEY March 3, 1931. C BUSHNELL 1,794,582

TRAIN CONTROL Filed May 10. 1924 9' Sheets-Sheet 9 Pump GovernorPatented Met. 3, iesi cnannns s. BUSHNELL, or nocnnsrpn, newY.ORK,1ASSIGNOR 'ro GENERAL RAILWAY SIGNAL COMPANY, on noonnsrnn, NEWYORK 'rnA-rn'oonrnoi.

Application filed May 10, 1924. Serial Ne. 712,259.

This invention relatesto automatic'train control system for railroadsand deals more partlcularly with the problem of mamtainmg or enforcingvigilance on the part of the engineerin obeying the unfavorableindications of the trackway block signals, or cab signals if used.

According to the theory on which'the present invention may be said to bepredicated, it'is desirable, in designing an automatic train controlsystem, to maintain to the highest degree the vigilance and care of theengineer in the handling of his train which exists at present andaffords a very high degree of safety. In other words, it is consideredeX )edient to avoid substitution of the safety a orded by automaticdevices for that now given by the engineer, making the automatic traincontrol systemof such a character as to supplement the present vigilanceand care of the engineer. It is thought that a train control system ofthis type would surely add to the safety of train movement, retainingall of the safety at present obtained and providing the automaticprotection in addition.

Roughly speaking, the object of an automatic train control system is tostop the train or reduce its speed, if safety requires, in the eventthatthe engineer fails to do so. This means that it becomes necessary todetermine automatically what the safe speed for a train is at difierentpoints in its travel under different conditions oftraffic and-imposeautomatic control of the brakes if thesev safe speed limits areexceeded. As a practical proposition, on account of the variation ingrades, braking power of trains, block lengths, and other practicallimitations, it becomes very difficult to accurately determineautomatically the safe speed limits at all points, with the result thatthe speed'limits which are enforced by the system of train control aremore or less inaccurate in prac tice and frequently represent acompromise between conflicting factors- One simple way of enforcingvigilance of the engineer is to inflict some sort of penalty wheneverthe engineer fails to control his train properly and the automatic traincontrol system has to apply the brakes. In

short, .every automatic brake application is accompanied by a penalty.In carrying out this scheme :of maintaining vigilance, it becomesnecessary for the engineer tohave the speed of his train at all timesbelow the arbitrary speed limits" automatically set up, that is, theengineer must keep below the dead-linevof automatic control in order toprior to such automatic brake application. In other words, the engineermay suppress the penalty associated with the automatic brake applicationby taking suitable action prior thereto. According to this invention,the engineer may suppress the penalty by manually controlling the brakesin such a fashion as to bring about a stop or reduction in speed of thetrain justas effectively as would be brought about by the automaticcontrol. Theidea is that, if the engineer goes about slowing down orstopping the train himself before the automatic control takes efi'ect,he has manifested his vigilance in the best fashion and is entitled toavoid the penalty even though an automatic brake application shouldoccuron account of the inaccuracies of the arbitrary speed limits.

This invention is specially concerned with theproblem of providingautomatic devices operating "only if the engineer has brought about theproper brake control in time to justify suppression of the penalty. Inthis connection, it is reasoned that, inasmuch as the manual brakeapplication re.- quired-is "assumed to be the equivalent or a substitutefor the automatic brake application, such manual application should beof plaining more specifically, the theory is that the engineermayproperly suppress the penalty it he places the engineers brake valveinthe service position before exceeding the critical speed limits, sincesuch movement initiates a manual brake application as promptlysis-necessary for safety.

; With the ordinary type or" air-brake equipinent, if the engineer Wererequired to keep this enginee'rs brake valve in the service position fora considerable time in order to suppress the penalty, there would be anunnecessary over-reduction in the brake pipe pressure and Waste of air.Hence, it is desirable to provide additional means permitting theengineer to lap his brake valve, provided he has kept this valve in theservice position long enough to assure an adequate brake application.One type of such means, herein disclosed, consists of a time measuringdevice which permits lapping of the engineers brake valve if it has beenheld in the service position for a time (about six or seven seconds)sulficient to reduce the equalizing reservoir pressure and assure anadequate application of the brakes. Another type of such means operatesupon the drop in pressure in the equalizing reservoir and permitslapping of the engineers brake valve after the equalizing reservoirpressure has been reduced the desired amount.

Since the penalty under consideration is associated with the automaticbrake application, this penalty may be suppressed by preventingoperation of the devices causing such brake application, inasmuch as thepenalty exists only if there is an automatic brake application, and a.suppression of operation of such automatic brake applying mechanismcarries with it the suppression of the penalty. On the other hand, sinceit is the penalty which it is desired primarily to suppress, the systemmay be organized on the basis of suppression ot penalty only, allowingthe automatic brake applying mechanism to operate each time the criticalspeed limits are exceeded, irrespective of What action may have beentaken by the engineer.

' The latter arrangement has the advantage that the automatic brakeapplying mechanism is kept in good operating condition by frequent use;whereas in the former arrangement, this mechanism, except for occasionaltests, never operates except in thos rare cases of automaticallycontrolling the air-brakes of trains for train control purposes hasreference to limiting the amount of brake pipe reduction occurring uponan automatic brake application. Those familiar with the airbrake artwill readily appreciate that the brakes are applied to the fullestextent after a certain limited reduction in brake pipe pressurehas beenmade, and further reduction in brake pipe pressure is merely a Waste ofair which must be replaced before the system has been re-charge'd tonormal. Now, where there is a suppression of penalty by a timely manualbrake application, it is especially important that the brake pipereduction occasioned by the respective manual and automatic controlshould be correlated so as to avoid an over-reduction; and moreparticularly it is desirable that the automatic mechanism should cut offas soon as the desired reduction has been made, whether due in Whole orin part to manual control, or to automatic control.

Another aspect of the problem of automatic braking refers to what isgenerally known as split application. In handling the brakes on atonnage train, it is frequently expedient to make the application of thebrakes by two or more separated reductions in brake pipe pressure so asto govern the slack and avoid shocks between cars. Conse quently, thepenalty suppressing means should preferably permit the engineer to makesplit applications; and this requirement modifies in some particularsthe character of the devices determining that an adequate reduction inbrake pipe pressure has been made. lVhile the automatic brake applyingmechanism of this invention may be organized to give automatic splitapplications, it is considered that the suppression of penaltycharacterizing the invention makes such automatic split applications ofless importance, for the reason that the engineer may split his manualapplications and get the slack under control before exceeding thecritical speed limits.

The principal and primary objects of this invention are to providevarious forms of devices, and organizations and combinations of devicesto meet these various requirements and problems briefly outlined above.The fundamental principles of the invention have been worked out inseveral forms, and have also been applied to different types of speedcontrol systems. The particular disclosure, however, is moreillustrative of the character of means constituting the presentinvention than a comprehensive showing of all ways in which theinvention may be practiced; and it should be understood that theinvention is not limited to any particular structure or organizationherein disclosed, but is susceptible of adaptation and medication tomeet the needs of any particular situation.

Various specific objects, purposes, advan tages, and characteristicfeatures of the inventionwith appear as the description progrosses." i

. In describing the invention in detail reference will be had to theaccompanying draw ings in which:

1 shows the trackway equipment of a train control system of theintermittent timedistance interval type having the present inventionapplied thereto, and also illustrates the permissive speed and brakingcharacter istics for one particular block;

g. 2 illus rates the usual engineer s brake valve having a valveactuator applied thereto, whereby an unpreventable brake applica tionmaybe made automatically, and further shows means for suppressing apenalty if an automatic brake application is anticipatedby a manualbrake application;

Fig. 3 shows the car-carried circuit arrangement of a train controlsystem ofthe time-distance interval type of Fig.1, the apparatus shownin Fig. 2 having been shown conventionally V V Fig. 4- illustrates thecar-carried and trackway apparatus of a train control system of thecontinuous inductive type having the present invention applied thereto;

Fig. 5 illustrates a penalty suppressing means in which a miniaturebrake cylinder having a pressure therein corresponding to that existingin the main brake cylinders i employed so as to determine when anadequat brake application has been made. i

F Gillustrates a modified arrangemen for determining when an adequatebrake application has been made.

Figs. 7 and 8 illustrate a still diilerent modified arrangement forsuppressing the penalty, in which predetermined reduction from normal inthe equalizing reservoir pressure suppresses the penalty; and alsoserves to permit the engineer to return thelrotary valve to'the lapposition after an automatic brake application has been ei'l'ected, toprevent excessive venting by such automatic application;

Fig. 9 shows the trackway equipment and a portion. of the car-carriedequipment of a two-position continuous inductive train control system,and graphically illustrates how the speed of the train may be reduced ina cantion block for different entrance speeds without the infliction ofa penalty; I

Fig. 10 shows the remainder'or" the earcarried equipment shown in Fig. 9

Fig. 11 illustrates a modified form of pe alty suppressing means similarto that shown in Fig. 10; V

ll shows a penalty suppressing means like that shown iii-Fig. 11 buthaving a modified form of contact associated therewith which closes acircuit when a predetermined degree of brake application has beeninitiated; and

Fig. 12 illustrates a train control system similar to that shown in Fig.l in which the penalty alone is suppressed without suppressing automaticoperation of the brake. control device, and in which a separate bra reapplying device is used which l mits the degree of brake applicationregardless of a concurring or preceding manual brake application.

In order to fully disclose the manner in which the invention may beapplied to various types of train control systems, the invention hasbeen illustrated in connection with two entirelydiiierent systems,namely (1) the intermittent inductive time-distance interval speedcontrol type; and the continuous inductive speed control type. The firstportion of the specification is directed to the intermittent type andthe latter part to the continuous inductive type.

Intermittent system Track way apparatue.lteferring particularly to Fig.1, there has been shown trackway apparatus for an. intermittenttime-distance interval type train control system applied to a portion ofautomatic signal territory. The track rails 1 are divided by. insulatedjoints 2 into blocks, the block I and the adjacent ends of two otherblocks H J being shown. Since the various blocks are the same, likeparts of each block are designated by like reference characters withdistinctive exponents. Although the train control system in question maybe used in connection with traekway signals of any type, either colorlight, position light or semaphore signals, semaphore signals Z havebeen shown conventionally without illustrating their well-known controldevices and circuits.

The exit end of each block is provided with a suitable source oftrackway energy, illustrated as a battery 8; and the entrance end isprovided with a track relay 4:. On the right hand side or the track, thedirection of trafiic being fromyleft to right as indicated by the arrow,are pairs of trackway elements T for inductively transmitting controlinfluences to suitable car-carried apparatus under cantion trafficconditions of the block. Since the car-carried apparatus, as will appearhereinafter, responds only to two successive control influences in lessthan a predete mined time, only one element T of each pair need be madeinactive under clear trafiic cond ions, the other element always beingactive. Each of these track elements T (see Fi 3) comprises a U-shapedcore 5 preferably constructed of a high grade of laminated magneticmaterial terminating in enlarged pole pieces 6. The controllable trackelement is also provided with a coil 7 on its core 5 which is normallyclosed in a circuit of low resistance through the front contact 8 of aline relay 9. Referring to the block 1, these variousline relays 9 ofeach'blocl: are connected in me ple across line wires whicl under cleartranc conditions, are energized by the battery 10 through the frontcontact 11 of the track relay P.

In Fig. 1 there has been gran ically illustrated by vertical andhorizontal dotted lines the speed limits set up at the three controlpoints at which the pairs of track elements T are located. In thisdiagram the solid line 12 represents the speed-distance brakeapplication curve of a certain train, the vertical distancesrepresenting miles per hour, and tie horizontal distances representingpoints in the block in question. The horizontal dotted line 13represents the speed limit enforced by the pair elements T, the dottedline i l the speed enforced by elements T, and the dotted line 15represents the speed setup by the elements T. It is thus noted that thetrain may run at speeds at various points in the blocks as indicated bythe dotted line 16 without exceeding the permissive speed limits. Asmore clearly pointed out hereinafter, the train may travel at speeds asindicated by the dot-and-dash line 17 under caution traflic conditionsif the engineer has anticipated the automatic brake application byeffecting an adequate brake application or initiating such a brakeapplication.

Oar-carried apparatus EZectm-gmcmnatic valve EPV.As an au tomatic brakeapplying dev1ce, an electropneumatic valve EPV has been shown in Fi 2which may be used to vent the brake pipe directly, if its wlndlng 20 1sdeenergized, may

actuate a suitable brake valve actuator, such gized, the valve 23 beingmaintained closed by a compression spring 24, the weight of the valves21 and 23, the armature 22 and the valve stem 25.

Brake cal 0e actuato1.1n Fig. 2 there has been illustrated the usualengineers brake valve BY, including the usual rotary valve provided withstandard ports, from which t ie valve cap has been removed and for whicha special cap 28 has been substituted. This cap 28 is provided withopposed cylinders 29 and 30 in'which move pistons 31 and 32 connected toether by a rack 33.

Extending up from the usual rotary valve (not shown) is a valve stem 3don which is pivotally mounted a pinion having two upwardly extendingpins which are adapted to engage the actuator plate AP. Movement o therack 33 in one direction or the other otates the pinion 35 and actuatorplate AP in the corresponding direction; Directly above the actuatorplate AP is a valve plate VP, which is directly connected to the valvestem 34 in any suitable manner, so that rotation of this plate VProtates the rotary valve. ilirectly above the valve plate VP is a handlenlate HP, which is directly connected to the "leeve 36 to which is keyedthe usual enineers brake valve handle 3?.

Under normal operating conditions, when the winding 20 of the'valve EPVis energized, main reservoir pressure is present in both of thecylinders 29 and 30, and the rack 33 is moved to the left hand extremeposition, because the cylinder 29 is larger than the cylinder 30. Thehandle 37 is directly coupled to the valve plate VP by the latch 38 heldin position by a coil spring 19. Under such normal conditions, thehandle 37, which is shown in the normal running position, may be movedto the release position, carrying with it the valve plate VP and handleplate HP held together by the latch 38, so that the engineer may applythe brakes or release them without interference by the actuatormechanism, the lap, service and emergency positions of the handle nothaving been specifically indicated.

Nhen an automatic brake application is initiated as a result ofdeenergization of the valve EPV, causing the rack 33 to move toward theright because 'the cylinder 29 is vented to atmosphere, the actuatorplate AP moves in a counter-clockwise direction; and during the firstportion of its movement (this being an idle movement), the cam 39 raisesthe latch 38 and thereby unlatches the handle plate HP from the valveplate VP. Further movement of the rack from the left to the right movesthe valve to the service brake applying position by reason of engagementof the upstanding lug 26 on the actuator plate AP with the extending arm27 of the valve plate AP. The engineer cannot hold as, so to speak, orprevent an automatic brake applicationby moving his handle 37 to therelease position, because the engineers valve is unlatched from thevalve plate and rotary valve, as far as movement in the clockwisedirection of the handle is concerned; but the service position, by theengagement of lug 26 with the extending arm 2?, but will not again movethe valve to therunning position when the device EPV is again energized,because there is no mechanical connection between the actuator plate'APand the valve plate VP for movement'o'f the actuator plate in theclockwise direction. This'is desirable because it requires a positiveact by the engineer each time the brakes are released.

Penalty and suppressing mca-ns.ln the particular form of the inventionshown, the penalty imposed upon the engineerfor negligence or neglect totake the appropriate action consists in requiring the train to bebrought to a stop before the brakes can be released and the trainproceed at speed. This is accomplishedby providing a suitable resetswitch RS, which is so located on the locomotive that itis accessibleonly by one standing on the ground, and which is so protected that itcannot be held closed. Consequently, when the engineer fails to take theappropriate action in manifestation of his vigilance, and the automaticapparatus on the locomotive assumes afcertain condition, the brakescannot be released and the train proceed, until it has been brought to astop and someone has operated the reset switch from the ground.

The embodiment of the invention shown utilizes electrical control ofdevices primarily, and hence, the penalty inflicting means,together withthe means for suppressmg such penalty, involvethe opening and closing ofcontacts. As apart of the penalty suppressing means, the engineers brakevalve I is'provided'withcontacts which are opened and closed in certainpositions of the. brake valve. In the form shown in Fig. 2, on thesleeve 36, to which the engineers brake valve handleB? is fixed, is acollar 420i insulating materialto which are fastened contact strips orsegments 43, {la and l5;'and adjacent to these segments are palrs ofcontact fingers" 46, 47'and48, which are bridged by said segments indifferent positions of the valve handle. The contact finger 43 is ofsuch length that it bridges and electrically con-- nects its cooperatingpair of fingers 46 if the engineers valve handle is in the l -P. theservice, or the emergencyposition. Similarly,itl16 contacts. a abridgetheir respective pairs 'ofcontact' fingers withthe engineers valvehandle in either the service or the emergency'position.

For reasons outlined hereinbetore, it is de sirable, in connection withthe suppression of the penalty, tohave automatic, mammasponding if, andonly. if, the engineer'jhas made the desired manual control or air-brakesystem suflicient'to assureabralre application of the requiredintensityQ In this particular arrangement, under consideration, it isassumed that theengineerhas exercised therequired manual control-when hehas madea certain predetermined reduction in the pressure in'theequalizing reservoir of the airbra re system. The operation of the usualtype or" air-brakes'ysteni is well-known, and

the function of the equalizing reservoir pressure is familiarto thoseskilled in the art, so 7 i it will be sufficient to point out thetareduetion in equalizing reservoir pressure is automatically followed bya reduction-in brake pipe pressure to correspond, and that so far as themanual control of the air-brake system is concerned,tl1is has been fullyaccomplished as soon as the equalizing reservoir pressure has beenreduced the desired amount. a

Forthe purposes of this disclosure it has been assumed that the speedrestrictions automatically imposed by the train control system will bebased upona full service brake appli= cation, corresponding to fullequalization of pressure between the auxiliary reservoir and brakecylinder of each car. .Roughly spealn ing, such a full serviceapplication represents about 20 pounds reduction in the brake pipepressure, and correspondingly in the equalizing reservoir pressure."With the typical equipment it takes about 6 or 7 seconds to make 'a' 20pound red c ion in equalizing reservoir pressure. Putting it anotherway, if theengineers brake valve ishe-ld in the service position for 6or 7 seconds, the pres-, sure in theequal zing reservo1r will drop inthis time sufiicient toproduce substantially a full service application.In short, if we measure the. time that the engineers brakehasabeen'inthe service position, without any intervening releaseorrecharge, is equal to 6 or? seconds.

. Referring now tothe specific means shown in Fig. 2, a cylinder 50 hasa movable piston 51 therein, which is urged in one direction (to theright, as shown) by a compression coil spring 5.2. Ibis pist n 51provided with a packing or rings, in accordance with approved practice,so as to prevent leakage by it; and to insure a quick or snap movement,this piston has ridges on its faces cooperating with gaskets in theextreme position of the piston.- Insulated contact disks or members 53and 54 are fixed to the rod or plunger of the piston 51, and engagepairs of fixed con tacts, shown conventionally as'arrows, when thepiston has shiftedto its extreme left hand position. V

The right hand side of the piston 51 is in communication with a smallcapacity reser voir 55. The pressure in this reservoir 55 is controlledby two electro-pneumatic valves DV and RV of suitable construction,which in turn, are controlled electrically in accordance with theposition of the engineers brake valve handle. The valve DV, ifdeenergized, connects the reservoir 55 to atmosphere, but if energizedcloses its exhaust. The winding of this valve DV has its energizingcircuit through the contacts l3 l6 of the engineers valve, so that saidvalve DV is energized if the engineers valve is in the lap, service,oremergency positions, but is deenergized for the running or releasepositions. The other valve RV, if energized, connects a suitable sourceof pressure, in this instance the brake pipe, to the reservoir 55through an adjustable restricted orifice 56, so that the flow ofpressure into said reservoir varies in accordance with time. If thevalve RV is deenergized, such supply of pressure is cut olf. This valveRV is energized by a circuit through the contacts l5l8 closed with theengineers brake valve in the service or the emergency positions.

With the engineers brake valve in the normal running position, the partsare in the position shown in Fig. 2, both of the valves DV and RV beingdeenergized, the reservoir 55 at atmospheric pressure, and the piston 517 held in the right hand position by its spring.

When the engineer moves his brake valve to the service position, both ofthe valves DV and RV are energized, the valve DV closing and cutting offthe exhaustfrom the cylinder 55, and thevalve RV opening to admitpressure at a slow rateto this reservoir. The size of the reservoir 55and the area of the restricted orifice 56 ar'e selected so that afterthe expirationof the desired time (assumed to be 6 or 7 seconds), thepressure inthis reservoir builds up to the point where, acting on. theexposed right hand face of the piston 51, it overcomes the tension ofthe spring 52 and moves the piston toward the left. As soon asthe'piston5l starts to move to the left, it breaks the gasket seal andexposes a larger area to the pressure in the reservoir, whereupon thepiston shifts quickly to its extreme left hand position, since theincreased area exposed to pressure more than compensates fortheincreased tension of the spring due to contraction. \Vhen the piston51 reaches its extreme left hand position, the contact members 53 and 54engagetheir cooperating pairs of contacts. During the time that theengineers hrakevalve was in the service position to bring about thisresult, the equalizing reservoir of the regular air-brake equipment was,of course, being vented; and before the expiration of the 6 or 7seconds, it is certain that the prcssure'in this equalizing reservoirhas been exhausted through the preliminary exhaust port in the engineersbrake valve to bring about the desired reduction. this time, theengineer is supposed to lap his valve, thereby arresting further ventingof the equalizing reservoir pressure and avoiding over-reduction inbrake pipe pressure and useless waste of air. lVhen the engineer moveshis valve to the lap position, the valve RV is deene'rgized on accountof the opening of the contacts 45 l8, while the valve DV is keptenergized and maintains the pressure in the reservoir 55 to hold piston,51 in its left hand position and keep contact disks 5354 in theircircuit closing position.

If the engineer should attempt to release the brakes by moving his valveto the running or release position, the valve DV is deenergized andopens to exhaust the pressure in the reservoir 55 immediately, whereuponcontact disks 5354.- at once assume the open position, to cause theactuator to again operate the brake valve to the service position, andenforce speed restrictions as more particularly pointed out hereinafter.While the engineer cannot release the brakes, he may split the reductioninto two or more stages, moving the valve back and forth between theservice and lap positions. In the service position, the valve RV isenergized and pressure builds up in reservoir 55 in accordance with thelapse of time; and solong as the engineer does not go beyond the lanposition to the running or release position, the valve DV is maintainedenergized to hold what pressure may have been built up in the reservoir55. It will be evident that the piston 5l does not shift until theaccumulated or total timethat theengineers valve has been in the serviceposition equalsfi or 7 seconds. By virtue of this arrangement, theengineer may make a partial application of the brakes to adjust theslack before exceeding the critical speed limits, and is not necessarilyrequired to make his man ,ual application all in one stage. After thecritical speed limits are exceeded, however, the engineer must maintainhis brake valve in the service position until the necessary reduction inequalizing reservoir. pressure has been made. In. other words, theengineer may split his applications'asmuch as he pleases before crossinthe dead-line of permissible speed limits, but after crossing this line,he must keep his brake valve in the service position until the propermanual brake application has been set up,it being obvious that this isnecessary to be sure of safety, inasmuch as the speed-limits are basedupon a continuous one-stage reduction, and to assure undermostunfavorable circumstances the equivalent manual application, allreductions after crossing the dead-line should be made in one stage. i

Influence receiving car element. The ref: erence character L designatesa car-carried element comprising an inverted til-shaped core oflaminated magnetic material terminating in enlarged pole pieces. Thelegs of this core '59 are provided with a primary coil P and a secondarycoil B respectively.

This car element L is preferably supported:

from the truck of the railway vehicleina manner so as to cooperate withthe track ele ments T (see Fig. 1) through a'small intervening air gapof from 1 to 2 inches, the

middle of thisair gap being,say, 3 to 3% inches above the top of thetrack rails.

' Relaya-The car-carried apparatusof the.

intermittent time-distance interval system shown in Fig. 3 includesrelays GB, RB, BR

and PR. -The first three of these relays are preferably sensitive andimmune to jars and vibrations, this being accomplished by making theirarinaturesvery light and well-balanced and by supporting. them about avertical axis so that swinging and jarring of the railway vehicle willnot tend to operate such armatures. The penalty relay PR need not befrom thetrackwayapparatus in less than a certain intervalof time, it isnecessary to have a reliable time elementdevice on the vehicle whichmeasures the time between successively'rece ved controlinfluences. Inthe system shown in Fig. 3 this time element (18-.

vice is one that functions on the principle of accelerationordeceleration of a mass similar to timing mechanism in watches. 7

This device TE hasbeen shown conventionally and comprises a shaft towhich is fastened a balance wheel '61. This balance wheel 61 is held inits normal'position by a time starting magnet TS acting on an arma ture62 fastened to the non-magnetic balance] This shaft 60 and the'balancewheel 61; wheel 61 are biased so as-to assume an inter- ,mediateposition substantially 90 toward the right of its normal position, inwhich it" is: shown, by aspiral spring 62, and is pro vided withcontacts 63'and-6i adapted to con tact withstationary contacts 65 and 66re-. spectively during different parts ofthe full oscillation of thewheel. If the time starting magnet TS is momentarily deenergized, thebalance wheel 61 will be swung in the clock wisedircction, and passesits biased position at substantially 90 making a swing of almost 180,after which it will swing back almost to its initial position, and ifthe time starting magnet TS is again'energized will again be attractedto its normal position. Speed responsz'oc desicc.-One element of thecar-carried apparatus is speed responsive device which reflects thespeed at which the vehicle is traveling at any point along the trackway;and in the'particular arrange ment shown this device G is of thecentrifugal type, including a shaft 69 driven from the wheels of thevehicle in any desired manner. @n this shaft 69 is pinned a sleeve 70and is slideably supported a collar 71 having a contact disk72'connected thereto but insulated therefrom. To the sleeve 70 and thecollar 71 are pivotally secured links 73 which are pivotally connectedat tlieir'free ends to balls 74, a compressioncoil spring 75 surroundingthe shaft 69 tending to separate this sleeve and collar as far aspossible. Rotation of the shaft69 causes the fly balls 7% to sep arateand pull the collar 71 down against the tension of the spring 5 so thatthe contact disk 72 assumes a position depending on the j speed oftheshaft 69 and closes a circuit when the speed of thetrain is less thana certain value, assumed to be about 20 miles per hour.

Operat'ion of intermittent eg stem Figs. 1 to 3 arrangement shown, theprimary coil P- of the car element L is energized by the followingcircuit :'be ginning at the terminal B, wire;

77, primary coil P, wires78 and 79, neutra point NP, through discharge-resistance '80,- I

back to common return wirerC. The fiowof current through ,lZlHS circuitcauses the neu tral point NP toassume a certain intermediate potentialbetween that of he terminals Under norinal conditions of the apparatusshown, the control relay CR and secondary coil S are connected in seriesbetween the terminal B and the neutral pointNPby a'cir-" cuit which maybe traced as follows:eter- I minal B, wire 81, front contact 82 of thecon-' trol' relay CR, wires .83- andfSt, winding of vlliththis controlrelay CR energized,.the

following circuit for the repeater relay RR may be traced:beginningat-the terminal 13 of the battery, wire 81, front contact}87 wires 88and 89, winding of the repeater -rc-- the repeater relay RR, wire 93,back to comk mon return wire C.

Another circuit is energized by the. control relay CR when energizedwhich includes the same front contact 87 and which may be traced asfollows :beginning at the terminal B, wire 81, front contact 87-, wires88 and 97, lower winding of the brake control relay BR, wire 98, frontcontact 99 of the brake control relay BR, and wire 100 back to commonreturn wire C. r

The circuit just traced is a stick circuit for the lower winding of thebrake control relay BE. A stick circuit for the upper winding of thisbrake'control relay BB is closed when the time element device TE is inits normal position and may be traced as follows :beginning,at theterminal B, wire 101, contacts 6365 of the time element device, wire102, upper winding of the brake con trol relay BR, wires 103 and 10 1,front con tact 105 of the brake control relay BR, and wire 100, back tocommon return wire C.

With the brake control relay BR energized, the electro-pneumatic brakecontrol device EPV is energized by a partial circuit starting from theneutral point NP as follows wire 106, front contact 107, wires 108 and109, winding 20 of the EPV, wire 110, reset push button switch 111 onlyaccessible from the ground, wire 112, back to common return wire C. Itis of course noted that the current flowing in this partial circuit alsoflows through the primary coil P, the complete circuit beginning at theterminal B of coil P and ending at C of the reset switch RS.

Vith these various circuits closed as de scribed, suificientcurrent willflow in the primary winding P to the neutral. point NP to set up a largemagneto-motive-torce 1n the car-element L establlshing a certain amountof flux, a large part of which, it is believed,

passes through leakage paths and a certain party of which. passesthrough the secondary coil S. i

It should be noted at this time that the: control relay GR is connectedin series wi h of depreciation of the source of energy, and

the like, causes a similar change in the potential across the secondarycoil S. In other words, weakening of the primary field causes loweringof the potential across the relay CR, so that asmaller impulse willcause dropping 01' this relay. The discharge resistance serves twopurposes, namely :permits the flow of current in the primary coil P whenthe device EPV is deenergized, and also acts as a discharge resistanceto prevent arcing at the relay contact when the circuit for the deviceEPV is opened.

Caution c0ndit0nsspeeci not excessive. Let us assume that the blockJ isoccupied by a train, thereby depriving the track relay 41 of energy andin turn deenergizing the line relays 9 so that the coils 7 on the trackelements T, T and T are open circuited, making these track elementsactive.

Let us further assume that a train, equipped with the car apparatusshown in Figs. 2 and 3, is moving in the block I and passes the firstpair of track elements '1 at a speed less than that shown by-the dottedline 15. When the car element L passes over the first track element '1,bridging of this element L by the core 5 causes a sudden increase offlux in the secondary coil S. This increase of nun, it is believed, islargely due. to a diversion of flux from the leakage paths, and to acertain extent is due to therincrease in the total flux passing throughthe primary coil P. As the car element L recedes from the track elementT, the flux passing through the secondary coil S again reduces tonormal. This sudden increase and decrease of the flux passing through orlinking the secondary coil induces a voltage in this coil correspondingto a single cycle of alternating current electromotive-force. The, coilS is preferably so connected in the circuit with the control relay CRthatthe first wave of this single cycle of voltage is in a direction tooppose the voltage of the battery, thus decreasing the current throughthe control relay CR enough to cause its armature to be retracted by itsbiasing spring (not shown) to the dotted line position. With the controlrelay CR once deenergized, it remains in its deenergized position untilrestored by some other means, because its stick circuit has been broken.

With the control relay deenergized, the stick circuit for the repeaterrelay ER is broken, thereby deenergizing this relay RR and in turn thetime starting magnet TS of the time element device TE, thus starting thetime element device on its cycle of operation in a clockwise direction.Deenergization of the control relay GB at this time also interrupts oneof the stick circuits (including the lower winding) of the brake controlrelay BB; but this relay, however, remains in its energized position byreason of its other stick circuit including contact 6365 of the timeelement device. As soon as the repeater relay RB assumes its deenergizedposition, a pickup circuit for the control relay GR is 00111 pleted asfollows :,beginning at the terminal 13, wire 113, back contacts 114 ofthe"repeater relay RR, wires 115 and 84, winding" of the control relayGR, wire 85, secondary coil S, wires 86 and 79, back to the neutralpoint NP. The completion of this pick-up circuit again picks up thecontrol relay CR which is then maintained up by its stick 'cir cuitheretofore traced. The restorationof the relay CR were deenergized whilethe time element IdeviceTE isperforming its cycle vof operation, and the'cont'acts63 and are broken, the st ck circuit for the lower windingofthe brake control relay BR would also be broken at this time, and thebrake control relay 1BR would assume its deenergized position. Since,however, it has been assumed that the speed ofthe train is less thanthat indicated by the dotted line 15, the time element device TE willhave'completed its cycle of operation and will again be in the normalpositionfbefore the car element L traverses the second track element ofthe first pair, so that passageof the car element L by the secondelement of the pair causes the same cycle of operationto take, placewithout deenergizing the brake control relay BR,

The same operationoccurs at the second pairof track elements T providedthe speed of the train is below the limiting speed indicated by thedotted-line 14, this speed limit being lower because the track elementsof this" pair are spaced closer together. At the pair,

of track elements T the speed of the train must be still lower to avoidautomatic con-- trol. A speed distance curve representing possible ortypical, performance which the exceeding these speed limits. Under thisasspeed limit for this pair, represented by the dotted line 15, and theengineers brake Valve is in the running position. As the train passesthe first track element of the pair =T, therelays GR and BB drop theirarmatures and are then restored by pick-up circuits including contacts114 and 66 the same as above described, and the balance wheel of thetime 7 element device is set'intomotion. Since the speed is assumed tobe too high, the train reaches the second track element of the pair Tbefore the balance wheel ofthe time element device has returned to itsinitial positionto close contacts 63-65.. Consequently, I

whenfthe relays CR and RR drop their armatures the second time at thesecond track element of the pair, both of the stick circuits for therelay BR are broken, one at the front contact 87' of the relay CR, andthe' otherat the contacts 6365' of the balance, wheel. Thearmature ofthe relay BR, therefore, movesat once to its retracted position" openingvalve 21. Pressure is then exhausted from behind the, large piston 31,andthe main reservolr pressure constantly acting on',

the small piston 32 shiftsthe rack 33 toward the right; As previously"explained, this movement ofthe rack 33, driving the actuator plate AP,first releases the latch 38 from engagementwith thearm 40, and then byrea-' son of contact .of'the lug 26 with the arm 27 ofthe valve plate"VP, drives the engineers'rotary valve, free from the handle'37, to theserviceposition. The engineer cannot prevent this movement, since hishandle is unlatched from the rotary valve for movement towards'ttherelease position; but the engineer can at any time move the rotary valvestill further to the emergency position.

Under the conditions assumed the engineer has not been vigilant andhence the penalty" should beenforced. This is accomplished byrequiringthe train to be stoppedand the reset switch RS operated, inorder to permit reenergization of the relay BR. It may be explainedherethat other forms of penalty are, of course, applicable to thearrangement shown in'Fig. 3. [For instance, instead of establishingthepick-up circuit for reenergizing thefrelay BR by manual manipulation ofthe resetswitch RS, this may be done by closure of cont-acts of :thespeed responsive device G,Jwhich are closed only after the speed of thetrain has been reduced-to a very low speed, such as two'miles per hour,meaning that the trainhas been brought substantially to a stop. Such amodificationis indicated in other forms of the invention here- I inafter explained and its applicability to this particular embodiment istoo obvious to require specific illustration.

When the engineerpushes this push button 111, the time element deviceTEin the meantime having returned to its normal position, a pickupcircuitfor the brake control relay BB is established which may be tracedas .fol-

lows :wi re 101, contacts 6365 of the time element deviceTE, wire102,upper windingand the engineer may release the brakes by moving hishandle to the service position, latching the handle plate HP tothe valveplate VP andthen returning the. handle to the running or releaseposition.

The enginer has been penalized by being required to come to a fullv stop.andget out to operate the reset switch RS, which is only accessiblefrom the ground;v and thisis proper because he was not vigilant and didnot either reduce speed or apply the brakesv manually. Further, itshould be noted that the. reset switch RScannot be maliciously tieddown, so as to avoid the penalty, because the push button 111 has tobein its upper position before the device EP V maybe energized and if,

tied down, the train could not move.

Caution condition-speed excessive-pen:

al tg suppresse,cl.Letus assume thatthe train in question is enteringthe block I under caution trailic conditions at a" speed ofabout 65miles per hour, asindicated by the dot-anddash line 17 at the entranceto the block I. Let us further assume that they engineer: is alert, andupon entering the block I, observes the caution signal, and realizingthat the speed of his train ishigher than the safe or restricted speedlimit provided by the train control system, initiates a manual brakeapplication to reduce speed, and accomplishes this initiation by puttinghis brake Valve in the service position before the train reaches thepair of track elements T.

As soon as the engineer puts his brake valve in the service position, apick-up circuit for the penalty relay PR is established and maybeconveniently traced as follows beginning at the neutral point NP, Wire106, front contact 117 of the relay BR, Wires 118 and 119, relay PB,wires 120 and 121, contacts 47 44 on the engineers brake valve, and Wire122 to the common return Wire 0.

traced includes the front contact 117 V of the gene relay BR; andconsequently. the engineer:

must-act before the relay BRis deenergized, as aboveexplained, by thepassage of the train over a pair of track elements at excessive speed.Once the penalty relay PR is energized, it is maintained energized by astick onds), the piston 51 (see Fig. 2) shifts and moves thecontact'dis'ks 53 and 54 into engagement with their cooperatingcontacts, where upon the engineer may move his valve to the lapposition, but no further, and the penalty relay-be maintained energized,the electrical connection to the common return wire C througlrwires 127and 128 being substituted for that through wires 121 and 122.

W'ith respect to the automatic operation just described, it is importantto note that the engineer must act before exceeding the speed limit inorder to have the penalty relay energized before the relay BR isde-energized and thereby'avoid the penalty which is inflicted with thisrelayPR de-energized, at the time the speed limit is exceeded.

Conseqnentl the engineer must'be alert and vig- 7 ilant in watching outfor the block signals occurs on the train, if he is to avoid thepenalty. This means that the engineer is obliged to keep a good watchalong the track and will be more likely to observe obstructions on thetrack than if his attention is diverted to signaling devices in the cab.If the engineer is vigilant and manually applies the brakes himself inobedience to the caution signal and excessive speed, then the train wi lbe safely stopped, even if the train control equipment should be for-anyreason out of order. Another point of interest is that it is notnecessary, in order to forestall the penalty, thatethe engineer shouldhave in effect a full service application before exceeding the.critical'speed limit, but is merely required to have his brake valve inthe service position; Safety is assured by this arrangement because ittakes about as much time for the automatic device to bring about a brakeapplication as it does by the engineers brake a e;-

Assuming that the engineer has been vigilant and the penalty relay PR-has been ener- V V gized, when the train passes the pair of track Itwill be observed that the circuit just,

vigilance and anticipatory manual brake application ofthe engineer doesnot avoid the automatic brake control, allot the automatic brake settingdevices operating the ergized, and the valve actuator (Fig. 2) operatesautomatically; but since the engineers valve has already been placedmanuallyin the service position, the operation of the valve actuator ismerely an idle movement, unlatching the engineers brake valve handle 37from I the rotary valve itself; As soon as the en-.

gineers brake valve has been in the service position for -6 or,Tseconds, the contacts close; and since the penalty relay PR is energized, the electro-pneumatic valve EPV is reenergized by a circuit asfOllOYVSPTCOlH mencing atthe neutralrpoint "NP, Wire'l23,

front contact 129 of relay Plh vvire 130, contacts 53, Wires 131 and10$),Ivalve EPV,vvii'e 110, push button .111 and wire 112 to the commonreturn W re. T he reenergization'ot the valve EPV restores the parts ofthe brake valve actuator to normal position, and the engineer maynow-lap his valve and avoid further reduct on in the equalizingreservoir pressure and the resultant reduction in brake v pipe pressure.If it should happen that the engineer has had his brake valve in theservice position 6 or 7 seconds before passing the pair of track devicesT at excessive speed, then the contacts 53 are, closed, and the valve jEPV Wouldnot be deenergized or the actuator operatedwhenthebralrecontrol relay BR is deener gized, In other Words, after apredeterminedreduction in equalizing reser-' voir pressure has beenmade, turther reduction by automatic operation is prevented.

The engineer cannot defeat, the objects of the invention, and i fheshould attempt to release the brakes after avoiding the penalty andbefore automatic restoration of the train control equipment, then assoonas the engineerplaces his brake valve in the release or runningposition, thevalve DV (Fig. 2) opens, theJreservoir pressure 55 isquickly vented, and the contacts 53 and 54; open, and

V the electro-pneumatic' valve EPV is immediately deenergized. Theengineers brake valve actuator is accordingly automatically operatedat.once,-taking the control of the brake valve out of the hands of theengineer v and automatically moving it to the service position. lheopening of the contacts 54, with the brake valve in the running orrelease position, interrupts the stick circuit for the relay'PR andcausesvits' armature to assume the retracted position; and since therelay BB is assumed to. be deenergized at this time, the relay PR cannot be energized again by putting the engineers brake valve in theservice position. Consequently, the penalty is inflicted, and also thevalve EPV remains deenergized irrespective of the In the particulararrangement shown, the pick up circuit for thevalve EPV includes thefrontcontact 129 of the penalty relay PR, so that this valve can beenergized aftera predetermined reduction has been made only in the eventthat the engineer is vigilant. This arrangement is adopted onthe theorythat such over-reduction as might occur would serve'as anadditional-penalty, requiring insoine instances extra-time to pump upthe brake. pipe pressurei Some users, however, may consider that suchoVer'-- reduction should be avoided at all times, and this can readilybedone by omitting the front contact-129-ot the relayPR and connecting thewire130 directly to the neutral point NP, such a change being so obviousas not to require illustration. With such a modified arrangement, theelectro-pneumatic val've EPV will be reenergized for each automaticoperation after a predeterminedreduction has been madein equalizingreservoir pres sure, corresponding to a time of 6 or 7 seconds,

whether the engineer has been vigilant-or not. Such re-energization ofthe'valve EPV' In the form of the invention just described,

it Will be noted that there can no objectionable action occuronaccountofthe simultaneous occurrences of the automatic and the vmanual brakecontrol, because the same dc vice, namely the engineers brake valve, is

used for both the automatic and the manual brake application.

7 Release after automatic operation-eagncer oz'gz'Zcmt.Assuming that theengineer has been vigilant, as above described, and also that speed ofthe train is above the arbitrary speed limits imposed by the system. Thetrain leaves the first pair of track elements T with the relay BRdeenergized and the penalty relay PR energized. I The engineers brakevalve may be still in the service position, or may have been moved backto the lap position, in case there has been time enough to effect apredetermined reduction. Vith the car equipment .in this condition,there are three different contingencies under which this equipment maybe restored to the normal condition to permit release of the brakes,namely:(a) the speed of the train is reduced below the permissive speedlimits at the next.

